Carlson



Filed May 25, 1956 IN V EN TOR.

United States Patent BREAK-AWAY DOOR CONTROL IVIECHANISM Martin Carlson,Brookfield, 111., assignor to George W. Houlsby, Jr., Chicago, Ill.

Application May 23, 1956, Serial No. 586,779

1 Claim. (Cl. 16-55) The present invention relates to what I refer to asa break-away door control mechanism. As used, this term refers to amechanism incorporated in or used with a door check or door operator,which permits the door to break away sharply and swing in the directionopposite to that of its normal motion, under emergency conditions.

One of the objects of the present invention is to pro vide a novelmechanism which normally operates in such fashion as to keep a swingingdoor under the control of a conventional door control mechanism butwhich, under emergency conditions breaks away sharply so as to permitthe door to swing relatively freely.

Still another object of the invention is to provide a novel door controlmechanism having the above characteristics, which permits an inwardlyswinging door to swing freely outwardly under conditions of excessivepressure against the door on the inside surface thereof, such as mayoccur during panic within the building.

Yet another object is to provide a novel accessory for use with a doorcontrol mechanism of the flush type which prevents people from beingtrapped within a building by a door which normally swings inwardly only.

Still another object is to provide a novel accessory having the abovecharacteristics, which is adapted for use with a single action doorcontrol.

Still another object is to provide a novel mechanism for use with aflush type door control which accomplishes the above and which enablesthe door control to hold the door either in the normal closed positionor alternatively in an open position so as to obtain ventilation whendesired.

Yet another object of the invention is to adapt a single action doorcontrol for operation with a breakaway door stop.

Still another object is to provide a novel device having the abovecharacteristics, which permits a controlled normally inwardly swingingdoor to be opened in the outward direction after which it remains openuntil manually re-set so as to be under the control of the door control.

Other objects and advantages will become apparent from the followingdescription of a preferred embodiment of my invention.

In the drawings, in which similar characters of reference refer tosimilar parts throughout the several views,

Fig. 1 is a longitudinal vertical sectional view through the adaptor ofthe present invention shown with the adaptor associated with a swingingdoor and a door of known construction; and

v Fig. 2 is a bottom view of the mechanism of Fig. 1, the spindle of thedoor control being shown in transverse section.

.In recent years, particularly in public buildings, the use ofcenter-hung swinging doors has become increasingly common. Such doors 1because of the top and bottom central pivot arrangement can swing eitherinice wardly or outwardly so far as the pivots are concerned, butordinarily are provided with some sort of flush mounted door controlwhich also provides the bottom pivot and which limits movement of thedoor. Ordinarily, after the door has been pushed open it is returned toclosed position by the door control and the most commonly used type ofcontrol mechanism has a built in stop to limit closing movement of thedoor to about five degrees outwardly of a position of alignment with thedoor jamb. The door jamb usually has some sort of door stop, and sincethe tendency of the door control mechanism is to swing the door fivedegrees or so beyond a position of alignment, the door is limited in itsreturn movement by the door stop.

This arrangement admirably suits the purpose of providing for theoperation of swinging doors which swing in one direction only. Usually,at the entrance to a building, the doors must swing inwardly becauseoutwardly-swinging doors would interfere with pedestrian traflic infront of the building. The problem associated with the use of doors ofthis type is that under conditions of panic within the building,.peoplein an attempt to get out may not be able to swing the doors inwardly toopen position, because of crowding at the building entrance.

The present invention is primarily a safety mechanism which releases thedoors for outward swinging movement automatically in such emergencies.

In my copending application, Serial No. 564,394, filed February 9, 1956,for Break-Away Door Stop, I have illustrated and described an improveddoor stop which ordinarily limits outward movement of a swinging door toa position in alignment with the door jamb, but which under excessiveloading on the interior surface of the door will break away sharply soas to permit the door to swing outwardly. A device of that charactersatisfactorily serves the purpose of preventing people from beingtrapped Within a building by an inwardly swinging door, providing thedoor control mechanism is of the double-action type; that is, a doorcontrol of the type which permits swinging of the door in eitherdirection. Door control mechanisms of this double action type, however,are more expensive and more complicated than single action door controlsand ordinarily are not used excepting under conditions where it isdesired to have the door swing in both directions during normal use.

The present invention adapts a single action door control, that is, onewhich swings through approximately degrees, for use with a break-awaydoor stop so as to accomplish the same purpose as a break-away door stopwhen used with a double action door control. The safety mechanism canalso be used with a single action door control if no door stop is used,if the single action door control is so adjusted as to center the doorin closed position with relationship to the door jamb on the basis ofthe stop mechanism built into the control itself.

It will be appreciated that the above remarks are directed both to doorchecks and to automatic door operators which swing the door open byrotating the lower door pivot. For those interested further, examples ofdoor checks and automatic door operators of the flush type form thesubject matter of' my US. Patents Nos. ,818, issued July 22, 1952,2,595,187, issued April 29, 1952, and 2,739,808, issued March 27, 1956.

Referring to the drawings, I have indicated the lower corner of aswinging door at 10. This door may be considered-as being of well knownconstruction and has a downwardly opening slot 12 formed in a channelmember at its lower edge. Near the rearward edge of this door a doorcontrol mechanism, indicated generally at 14, has the major portionthereof recessed into the floor so that the only portion showing is adress plate 16, substantially flush with the floor, and an upstandingspindle 18. This spindle also serves as the lower pivot for supportingand journaling the door for swinging movement. The upper end ofthespindle v18 is flattened ,as at. 20 on opposite sides, these fiat'spots being tapered toward each other at the top. Ordinarily anoperating'arm is secured within the channel 12 and has a recess orsocketin the lower face thereof substantially complementary in shape to theupper end of the spindle'l d so that when the arm is secured within thebottom channel 12, and the socket therein is slipped over the upper endof the spindle 18 with the spindle at the top of the door'lalso beingappropriately connected, any swinging movement" of the door iscommunicated in the form of rotationali displacement to the spindle 18.

The mechanism beneath the floor connected to the spindle 18 acts througha spring loaded means to return the spindle to the at-rest position,with the door closed, under the restraint of some checking mechanism,usually hydraulic in character. i I

' According to the teaching of the present invention, there is agenerally rectangular arm 22 which is secured in the door channel 12 bymeans of cap screws 24,'ver ticalpositioning of the door beingaccomplished by the use of a shim 26 of appropriate thickness. This armhas a cylindrical cavity 28 which extends upwardly from the lowersurface thereof well toward the top of the arm, this cavity beingconsiderably larger in diameter than the the diameter of the spindle 18.A cylindrical cupshaped member 30 fits the cavity 28 so as to be freelyrotatable therein, and the lower surface of this cupshaped member has asocket 33 therein which is substantially complementary to the upper endof the spindle 18. With the socket 33 fitted over the end of the spindle18, therefore, and with the cup-shaped member 30 seated in the cavity 28and with the door in place, the door is free to rotate without turningthe spindle 18.

Toward the right, as seen in Fig. 1, that is, toward the free edge ofthe door, the arm 22 is drilled horizontally through to the cavity 28 soas to provide a sliding fit for a generally cylindrical plunger 32. Theend of the plunger 32 which is toward the spindle 18 is shaped tofrusto-conical contour, as indicated at 34, and this end seats within aconical cavity 36 in the side wall of the cup-shaped member 30 when allof the parts are oriented as they should be with the door closed.Although it is not critical, a satisfactory apex angle for the conicalnose 34 is about 60 degrees.

Further toward the free edge of the door, that is, toward the right ofFig. l, a comparatively heavy coil spring 38 is so arranged within aslot 39 in the arm that one end bears against a spring base 40 which inturn is seated aganist the base end of the plunger 32 While the oppositeend of the spring bears against a spring base 42 backed up by a threadedabutment 44 extending into the right hand end of the arm 22. The outwardend of the spring abutment 44 has a hexagonal socket 45 therein, topermit adjustment by an Allen wrench of the compressive force of thespring 38 and hence the force tending to hold the tapered nose of theplunger in the socket 36.

So long as the plunger 32 is seated in the socket 36, no rotationalmovement as between the arm 22 and the cup-shaped member 30 is possible.On the other hand, torque applied to one of these members relative tothe other, if suflicient, will act to wedge the nose 34 of the plunger32 out of the socket 36, thereby permitting the arm 22 to turn about thecup-shaped member 30. There will be appreciable restraint under theseconditions because of the frictionalengagement of the flat end of theplunger 32 against the cylindrical surface of the cupshaped member 30.This frictional restraint is sufficient to retain the door in anyposition to which it is pushed, but will hardly be noticed by anyoneattempting to swing the door.

Although the optimum pressure exerted by the spring 38 and plunger 32will vary, depending upon the particular circumstances, including theangle of the nose 34. I have found that a satisfactory adjustment formost purposes is one at which the arm breaks free at a relative torqueas between the door and spindle 18 of about 150 foot-pounds.

It will be appreciated that when this advice is used with a singleaction door control adjusted so as to center the door relative to thejamb without the use of a separate door step, the door will operate inthe customary manner so as to swing freely inwardly, but not outwardlyso long as the force applied to the inner face of the door produces lessthan 150 foot-pounds of torque upon the spindle 18. At a higher reversetorque, the plunger 32 will be wedged out of the recess 36 and the doorwill break free so as to swing outwardly substantially withoutnoticeable restraint.

The preferred arrangement, as previously suggested, is to use thisdevice with the door control mechanism so adjusted that it tends toreturn the door to a position approximately five degrees beyondalignment with the door jamb and then to use a break-away door stop ofthe type previously mentioned to limit closing movement of the door to aposition in alignment with the door jamb.

When this arrangement is used, an excessive loading upon the interiorsurface of the door will cause the break-away door stop to release,thereby permitting free outward swinging movement of the door so far asthe door stop is concerned. After the door has swung approximately fivedegrees, the spindle 18 of the doorcontrol mechanism will reach thelimit of its movement and thereafter the arm 22 will break free of thecup-shaped member 30, so as to permit the door to continue its outwardswinging movement. By using this arrangement, the two break-awaymechanisms break in succession and therefore the force required toovercome their resistance is successive rather than additive.Furthermore, once the door stop has broken away, the inertia of themoving door will tend to carry it through the second phase of thebreak-away cycle, so that although two separate breakaway mechanisms areused, their total inhibiting effect upon outward swinging movement ofthe door is no more than one and is well within safe limits so far asproviding an emergency exit from the building is concerned.

Ordinarily a single action door control will permit a door to be openedslightly more than degrees. With the mechanism just described, the doorcan be pushed open to the limit of its normal movement and afterthespindle 18 will no longer rotate, an additional force against thedoor will cause the plunger 32 to be wedged out of the recess 36,thereby permitting the door to be swung beyond this position until it isrestrained against further movement by an adjacent wall. Once the doorhas been opened to this extent, if it is then released, the door controlmechanism will return the door toward closed position about 90 degrees,thereby leaving the door partly open for ventilation. Under someconditions, as soon as the door has been opened enough to break themechanism, the return spring in the door control will rotate the spindle18 to the position it normally assumes with the door closed, against therestraining effect of the flat end of the plunger 34 bearing against thecylindrical surface of the cup 30. Thereafter the doorv may be movedmanually to any desired position to obtain ventilation without rotatingthe spindle 18.

If operation is as first described, thatis, if the return spring in thedoor control is not quite strong enough to rotate the spindle to closedposition after the mechanism has broken free, much the same effect canbe obtained by jerking the door suddenly in an opening direction so thatthe tendency of the door control return spring to rotate 5 the cupmember 3%) relative to the arm 22 is supplemented by the inertia of thedoor control mechanism. Once this method has been used to open the doormore than necessary, the door can simply be pushed in the closingdirection to the desired position.

In any event, the door at any time can be returned to the control of thedoor control mechanism by swinging the door in the proper directionuntil the spindle 18 reaches the end of its travel and thereafter in thesame direction until the nose 34 snaps into the socket 36.

From the above description of a preferred embodiment of my invention itwill be apparent that modifications may be made in the structuredisclosed while still obtaining the benefit of the invention and thattherefore the scope of this invention is determined by the scope of theaccompanying claim.

Having described my invention, what I claim as new and useful and desireto secure by Letters Patent of the United States is:

A swinging door control safety device for a flush type door controlmechanism operating to supply a torque to return a door to closedposition after opening thereof in one direction and having a verticalrotatable spindle,

comprising an arm adapted for attachment in a recess in a horizontaledge of the door so as to swing therewith, a member journaled forrotation about a vertical axis in said arm, said member having means forattachment to said spindle so that said member rotates with saidspindle, spring loaded detent means in said arm having a portion thereofseated in a socked formed in said member for locking said member to saidarm for rotation therewith whereby the door attached to said'arm whenopened and then released is swung to closed position by the door controlmechanism, said spring loaded detent means and the socket being formedto provide tapered mutually engaging portions to form torque responsivecamming surfaces therebetween to wedge said detent means out of saidsocket to release said arm for rotation relative to said member whensaid door is pushed from closed position in an opposite openingdirection.

References Cited in the file of this patent UNITED STATES PATENTS1,065,145 Koerner June 17, 1913

